[Freeciv-Dev] (PR#9627) PATCH: correct some parameters in map generator and clean-up

["Marcelo Burda" <mburda@xxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=9627 >

Ok! i sow next one will bi too complex, finally this is ok to be include
there.

LAST CHANGES

assign_continents_numbers move to maphandle.c and extended to mesure
size of continents
now MASS_SIZE(nr) where nr is a ocean or a continent number (signus safe
code ) can be used to see the size of the water/land mass

tiny isles are avoided growing its if posible

small water mass (less than 8 tiles) are deleted, nice for gen5

gen 2-4 are not touched. tiny isle option still working for it, and gen
2-4 still makind tiny oneans of 1x1! These bugs has to be corrected with
a separate patch. this one only touch code used by mapgen 1,5

Marcelo



diff -ruN -Xfreeciv/diff_ignore freeciv/common/map.h freeciv_/common/map.h
--- freeciv/common/map.h        2004-08-13 21:08:52.000000000 +0200
+++ freeciv_/common/map.h       2004-08-15 08:37:17.099890368 +0200
@@ -621,7 +621,7 @@
 #define MAP_MIN_SEED             0
 #define MAP_MAX_SEED             (MAX_UINT32 >> 1)
 
-#define MAP_DEFAULT_LANDMASS     30
+#define MAP_DEFAULT_LANDMASS     35
 #define MAP_MIN_LANDMASS         15
 #define MAP_MAX_LANDMASS         85
 
@@ -629,11 +629,11 @@
 #define MAP_MIN_RICHES           0
 #define MAP_MAX_RICHES           1000
 
-#define MAP_DEFAULT_MOUNTAINS    30
-#define MAP_MIN_MOUNTAINS        10
+#define MAP_DEFAULT_MOUNTAINS    10
+#define MAP_MIN_MOUNTAINS        5
 #define MAP_MAX_MOUNTAINS        100
 
-#define MAP_DEFAULT_GRASS       35
+#define MAP_DEFAULT_GRASS       55
 #define MAP_MIN_GRASS           20
 #define MAP_MAX_GRASS           100
 
@@ -649,7 +649,7 @@
 #define MAP_MIN_RIVERS           0
 #define MAP_MAX_RIVERS           100
 
-#define MAP_DEFAULT_FORESTS      20
+#define MAP_DEFAULT_FORESTS      12
 #define MAP_MIN_FORESTS          0
 #define MAP_MAX_FORESTS          100
 
diff -ruN -Xfreeciv/diff_ignore freeciv/server/mapgen.c freeciv_/server/mapgen.c
--- freeciv/server/mapgen.c     2004-08-13 21:08:52.000000000 +0200
+++ freeciv_/server/mapgen.c    2004-08-15 09:57:42.289350072 +0200
@@ -25,6 +25,7 @@
 #include "game.h"
 #include "log.h"
 #include "map.h"
+#include "maphand.h" /* assign_continent_numberd(),MASS_SIZE(), MAP_NCONT */
 #include "mem.h"
 #include "rand.h"
 #include "shared.h"
@@ -75,8 +76,12 @@
 static int *river_map;
 
 static int *height_map;
-static int maxval=0;
-static int forests=0;
+static int maxval=0, seaval=0, reliefval=0;
+static int forests_to_be_placed =0;
+static int deserts_to_be_placed=0;
+static int grass_to_be_placed=0;
+static int plains_to_be_placed=0;
+static int swamps_to_be_placed=0;
 
 struct isledata {
   int goodies;
@@ -84,22 +89,32 @@
 };
 static struct isledata *islands;
 
-/* this is used for generator>1 */
-#define MAP_NCONT 255
-
 /* this is the maximal temperature at equators returned by map_temperature */
 #define MAX_TEMP 1000
 
 /* An estimate of the linear (1-dimensional) size of the map. */
 #define SQSIZE MAX(1, sqrt(map.xsize * map.ysize / 1000))
 
+/* define the 4 region of a Earth like map
+  =========================================================
+   0-COLD_LV                cold region: most ice/tundra/mountains
+   COLD_LV-TREOPICAL_LV     temperate region: all terrains types
+   TROPICAL_LV-WET_LV  tropical dry region: most dessert/mountains
+   WET_LV-MAX_TEMP     tropical wet region: most jungle/mountains
+*/
+#define COLD_LEVEL (10 * MAX_TEMP / 100)
+#define TROPICAL_LEVEL (65 * MAX_TEMP / 100)
+#define WET_LEVEL (80 * MAX_TEMP / 100)
+
 /* used to create the poles and for separating them.  In a
  * mercator projection map we don't want the poles to be too big. */
 #define ICE_BASE_LEVEL                                         \
   ((!topo_has_flag(TF_WRAPX) || !topo_has_flag(TF_WRAPY))      \
    /* 5% for little maps; 2% for big ones */                   \
    ? MAX_TEMP * (3 + 2 * SQSIZE) / (100 * SQSIZE)              \
-   : 5 * MAX_TEMP / 100  /* 5% for all maps */)
+   : COLD_LEVEL / 2  /* for all maps */)
+
+#define T_NOTPLACED T_UNKNOWN
 
 /****************************************************************************
   Returns the temperature of this map position.  This is a value in the
@@ -283,24 +298,72 @@
 }
 
 /**************************************************************************
-  make_mountains() will convert all squares that are higher than thill to
+  Checks if land has not yet been placed on tile at (x, y) 
+**************************************************************************/
+static bool not_placed(x, y)
+{
+  return map_get_terrain(x, y) == T_NOTPLACED;
+}
+
+/**************************************************************************
+  we don't want huge areas of grass/plains, 
+  so we put in a hill here and there, where it gets too 'clean' 
+
+  Return TRUE if the terrain at the given map position is "clean".  This
+  means that all the terrain for 2 squares around it is not mountain or hill.
+****************************************************************************/
+static bool terrain_is_clean(int map_x, int map_y,int thill, int my_high)
+{
+  int biger_me = 0;
+  square_iterate(map_x, map_y, 2, x1, y1) {
+    if (hmap(x1, y1) > thill) {
+      return FALSE;
+    }
+    if (hmap(x1, y1) > my_high){
+      if(map_distance(map_x, map_y, x1, y1) == 1) {
+       return FALSE;
+      }
+      if(++biger_me > 2) {
+       return FALSE;
+      };
+    }
+  } square_iterate_end;
+
+  if ((thill - seaval) * (biger_me)  > (my_high - seaval) * 4 ) {
+      return FALSE;
+  }
+  return TRUE;
+}
+
+/**************************************************************************
+  make_relief() will convert all squares that are higher than thill to
   mountains and hills. Notice that thill will be adjusted according to
   the map.mountains value, so increase map.mountains and you'll get more 
   hills and mountains (and vice versa).
+  TODO: extend to place abyss/ocean/sea relief in oceans
 **************************************************************************/
-static void make_mountains(int thill)
+static void make_relief()
 {
-  int mount;
-  int j;
+  int mount, total;
+  int j, thill = maxval * 0.8;
 
   for (j = 0; j < 10; j++) {
     mount = 0;
+    total = 0;
     whole_map_iterate(x, y) {
-      if (hmap(x, y) > thill) {
-       mount++;
+      if(not_placed(x,y)) {
+       total++;
+       if (hmap(x, y) > thill) {
+         mount++;
+       } else if(terrain_is_clean(x, y, thill, hmap(x, y))){
+         mount++;
+       }
       }
     } whole_map_iterate_end;
-    if (mount < (map_num_tiles() * map.mountains) / 1000) {
+    reliefval = thill;
+    if (mount * (map.mountains + map.swampsize + map.forestsize 
+                + map.deserts + map.grasssize ) 
+       < total * map.mountains  ) {
       thill *= 95;
     } else {
       thill *= 105;
@@ -309,15 +372,17 @@
   }
   
   whole_map_iterate(x, y) {
-    if (hmap(x, y) > thill && !is_ocean(map_get_terrain(x,y))) { 
+    if (not_placed(x,y) 
+       && (hmap(x, y) > reliefval 
+           || terrain_is_clean(x, y, reliefval, hmap(x, y)))) { 
       /* Randomly place hills and mountains on "high" tiles.  But don't
        * put hills near the poles (they're too green). */
-      if (myrand(100) > 75 
-         || map_temperature(x, y) <= MAX_TEMP / 10) {
+      if (myrand(100) > 70 
+         || map_temperature(x, y) <= COLD_LEVEL) {
        map_set_terrain(x, y, T_MOUNTAINS);
-      } else if (myrand(100) > 25) {
+      } else {
        map_set_terrain(x, y, T_HILLS);
-      }
+      }  
     }
   } whole_map_iterate_end;
 }
@@ -355,6 +420,24 @@
     }
   } whole_map_iterate_end;
 }
+/*************************************************************************
+ if separatepoles is set, return false if this tile has to kip ocean
+************************************************************************/
+static bool ok_for_separate_poles(int x, int y) 
+{
+  if (!map.separatepoles) {
+    return TRUE;
+  }
+  adjc_iterate(x, y, x1, y1) {
+    if(!is_ocean(map_get_terrain(x1, y1))
+       && map_get_continent(x1, y1 ) != 0) {
+      return FALSE;
+    }
+  } adjc_iterate_end;
+  return TRUE;
+}
+
+
 
 /****************************************************************************
   Place untextured land at the poles.  This is used by generators 1 and 5.
@@ -365,30 +448,17 @@
   struct tile *ptile;
   int T;
 
+  assign_continent_numbers();
   whole_map_iterate(map_x, map_y) {
     T = map_temperature(map_x, map_y); /* temperature parameter */
     ptile = map_get_tile(map_x, map_y);
-    if (T < 1.5 * ICE_BASE_LEVEL) {
-      ptile->terrain = T_GRASSLAND;
-    } else if ((T <= 2 * ICE_BASE_LEVEL) && myrand(10) > 4 ) { 
-      ptile->terrain = T_GRASSLAND;
-    }
-  } whole_map_iterate_end;
-}
-
-/****************************************************************************
-  Create tundra in cold zones.  Used by generators 1 and 5.  This must be
-  called after make_arctic since it will fill all remaining untextured
-  areas (we don't want any grassland left on the poles).
-****************************************************************************/
-static void make_tundra(void)
-{
-  whole_map_iterate(x, y) {
-    int T = map_temperature(x, y);
-
-    if (map_get_terrain(x, y) == T_GRASSLAND 
-       && (2 * ICE_BASE_LEVEL > T || myrand(MAX_TEMP/5) > T)) {
-      map_set_terrain(x, y, T_TUNDRA);
+    if (T < 1.5 * ICE_BASE_LEVEL && ok_for_separate_poles(map_x, map_y)) {
+      ptile->terrain = T_NOTPLACED;
+      map_set_continent(map_x, map_y, 0);
+    } else if ((T <= 2 * ICE_BASE_LEVEL) 
+              && myrand(10) > 4 && ok_for_separate_poles(map_x, map_y)) { 
+      ptile->terrain = T_NOTPLACED;
+      map_set_continent(map_x, map_y, 0);
     }
   } whole_map_iterate_end;
 }
@@ -401,8 +471,8 @@
   whole_map_iterate(x, y) {
     int T = map_temperature(x, y);
 
-    if (map_get_terrain(x, y) == T_GRASSLAND 
-       && myrand(15 * MAX_TEMP / 100) > T -  ICE_BASE_LEVEL 
+    if (not_placed(x, y)
+       && myrand(1.5 * COLD_LEVEL) > T -  ICE_BASE_LEVEL 
        && T <= 3 * ICE_BASE_LEVEL) {
       map_set_terrain(x, y, T_ARCTIC);
     }
@@ -423,14 +493,16 @@
 {
   const int DeltaT = MAX_TEMP / (3 * SQSIZE);
 
+  if(deserts_to_be_placed <= 0) { return; }
+
   if (abs(hmap(x, y) - height) < diff 
-      && map_get_terrain(x, y) == T_GRASSLAND) {
+      && not_placed(x, y) && count_ocean_near_tile(x,y) <= 2) {
     map_set_terrain(x, y, T_DESERT);
+    deserts_to_be_placed--;
     cardinal_adjc_iterate(x, y, x1, y1) {
       make_desert(x1, y1, height,
                  diff - 1 - abs(map_temperature(x1, y1) - base_T) / DeltaT,
                  base_T);
-     
     } cardinal_adjc_iterate_end;
   }
 }
@@ -443,125 +515,171 @@
 **************************************************************************/
 static void make_forest(int map_x, int map_y, int height, int diff)
 {
-  int nat_x, nat_y, T;
+  int T;
 
-  map_to_native_pos(&nat_x, &nat_y, map_x, map_y);
-  T = map_temperature(map_x, map_y);
-  if (map_get_terrain(map_x, map_y) == T_GRASSLAND) {
-    if (T > 8 * MAX_TEMP / 10 
-       && myrand(1000) > 500 - 300 * (T * 1000 / MAX_TEMP - 800)) {
+  if(forests_to_be_placed <= 0) { return; }
+  if (not_placed(map_x, map_y)) {
+    if ((T = map_temperature(map_x, map_y))> WET_LEVEL         && myrand(100) 
>  50) {
       map_set_terrain(map_x, map_y, T_JUNGLE);
     } else {
       map_set_terrain(map_x, map_y, T_FOREST);
     }
+    forests_to_be_placed--;
     if (abs(hmap(map_x, map_y) - height) < diff) {
       cardinal_adjc_iterate(map_x, map_y, x1, y1) {
-       if (myrand(10) > 5) {
+       if (myrand(10) > 5 || (T > WET_LEVEL && myrand(10) >  5)) {
          make_forest(x1, y1, height, diff - 5);
        }
       } cardinal_adjc_iterate_end;
     }
-    forests++;
   }
 }
 
 /**************************************************************************
-  makeforest calls make_forest with random grassland locations until there
-  has been made enough forests. (the map.forestsize value controls this) 
+  a recursive function that adds swamps to the current location and try
+  to spread out to the neighbours.
 **************************************************************************/
-static void make_forests(void)
+static void make_swamp(int map_x, int map_y, int height, int diff)
 {
-  int x, y;
-  int forestsize = (map_num_tiles() * map.forestsize) / 1000;
-
-  forests = 0;
-
-  do {
-    /* Place one forest clump anywhere. */
-    if (rand_map_pos_temperature(&x, &y,
-                                MAX_TEMP / 10, MAX_TEMP,
-                                T_GRASSLAND)) {
-      make_forest(x, y, hmap(x, y), 25);
-    } else { 
-      /* If rand_map_pos_temperature returns FALSE we may as well stop
-       * looking. */
-      break;
-    }
-
-    /* Now add another tropical forest clump (70-100% temperature). */
-    if (rand_map_pos_temperature(&x, &y,
-                                7 *MAX_TEMP / 10, MAX_TEMP,
-                                T_GRASSLAND)) {
-      make_forest(x, y, hmap(x, y), 25);
-    }
-
-    /* And add a cold forest clump (10%-30% temperature). */
-    if (rand_map_pos_temperature(&x, &y,
-                                1 * MAX_TEMP / 10, 3 * MAX_TEMP / 10,
-                                T_GRASSLAND)) {
-      make_forest(x, y, hmap(x, y), 25);
+  if(swamps_to_be_placed <= 0) { return; }
+  if (not_placed(map_x, map_y) 
+      && ( 2 * (hmap(map_x, map_y) - seaval) < myrand(reliefval - seaval)
+       || (map_temperature(map_x, map_y) > WET_LEVEL && myrand(40) >  30))) {
+      map_set_terrain(map_x, map_y, T_SWAMP);
+      swamps_to_be_placed--;
+      if (abs(hmap(map_x, map_y) - height) < diff) {
+         cardinal_adjc_iterate(map_x, map_y, x1, y1) {
+         make_forest(x1, y1, height, diff - 5);
+      } cardinal_adjc_iterate_end;
     }
-  } while (forests < forestsize);
+  }
 }
-
 /**************************************************************************
-  swamps, is placed on low lying locations, that will typically be close to
-  the shoreline. They're put at random (where there is grassland)
-  and with 50% chance each of it's neighbour squares will be converted to
-  swamp aswell
+  a simple function that adds plains or tundra to the current location.
 **************************************************************************/
-static void make_swamps(void)
+static void make_plain(int x, int y)
 {
-  int x, y, swamps;
-  int forever = 0;
+  int T = map_temperature(x, y);
 
-  for (swamps = 0; swamps < map.swampsize; ) {
-    forever++;
-    if (forever > 1000) {
-      return;
-    }
-    rand_map_pos(&x, &y);
-    if (map_get_terrain(x, y) == T_GRASSLAND
-       && hmap(x, y) < (maxval * 60) / 100) {
-      map_set_terrain(x, y, T_SWAMP);
-      cardinal_adjc_iterate(x, y, x1, y1) {
-       if (myrand(10) > 5 && !is_ocean(map_get_terrain(x1, y1)) 
-           && map_get_terrain(x1, y1) != T_SWAMP ) { 
-         map_set_terrain(x1, y1, T_SWAMP);
-         swamps++;
-       }
-      } cardinal_adjc_iterate_end;
-      swamps++;
-    }
+  if(2 * ICE_BASE_LEVEL > T || myrand(2 * COLD_LEVEL) > T) {
+    map_set_terrain(x, y, T_TUNDRA); /* in cold place we get tundra instead */
+  } else {
+    map_set_terrain(x, y, T_PLAINS);
   }
+  plains_to_be_placed--;
 }
 
-/*************************************************************************
-  Make deserts until we have enough of them.
+/**************************************************************************
+  make_terrains calls make_forest, make_dessert  with random free locations 
+  until there  has been made enough.
+ Comment: funtions as make_swamp, etc. has to have a non 0 probability
+ to place one terrains in called position. Else make_terrains can get
+ in a infinite loop!
 **************************************************************************/
-static void make_deserts(void)
+static void make_terrains(void)
 {
-  int x, y, i = map.deserts, j = 0;
+  int x, y;
+  int total = 0;
+  whole_map_iterate(x, y) {
+    if(not_placed(x,y)) {
+      total++;
+    }
+  } whole_map_iterate_end;
 
-  /* "i" is the number of desert clumps made; "j" is the number of tries. */
-  /* TODO: j is no longer needed */
-  while (i > 0 && j < 100 * map.deserts) {
-    j++;
+  forests_to_be_placed = total * map.forestsize
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize );
+  deserts_to_be_placed = total * map.deserts
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
+  swamps_to_be_placed = total * map.swampsize
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
 
-    /* Choose a random coordinate between 20 and 30 degrees north/south
-     * (deserts tend to be between 15 and 35; make_desert will expand
-     * them). */
-    if (rand_map_pos_temperature(&x, &y,
-                                65 * MAX_TEMP / 100, 80 * MAX_TEMP / 100,
-                                T_GRASSLAND)){
-      make_desert(x, y, hmap(x, y), 50, map_temperature(x, y));
-      i--;
-    } else {
-      /* If rand_map_pos_temperature returns FALSE we may as well stop
-       * looking. */
-      break;
+  /* tundra and plains is counted in map.grasssize */
+  grass_to_be_placed = total * map.grasssize / 2
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
+  plains_to_be_placed = total /* and tundra */
+      - forests_to_be_placed - deserts_to_be_placed - grass_to_be_placed;
+
+  /* the plasing loop */
+  do {
+    if(forests_to_be_placed > 0) {
+      /* Place one forest clump between Very Cold level and MAX_TEMP. */
+      if (rand_map_pos_temperature(&x, &y,
+                                  (COLD_LEVEL + ICE_BASE_LEVEL) / 2, MAX_TEMP,
+                                  T_NOTPLACED)) {
+       make_forest(x, y, hmap(x, y), 25);
+      } else { 
+        /* If rand_map_pos_temperature returns FALSE we may as well stop
+         * looking for forest. */
+       plains_to_be_placed += forests_to_be_placed;
+       forests_to_be_placed = 0;
+      }
     }
-  }
+
+    if(swamps_to_be_placed > 0) {
+      /* Place one swamp clump between COLD_LEVEL and MAX_TEMP.. */
+      if (rand_map_pos_temperature(&x, &y,
+                                  COLD_LEVEL, MAX_TEMP,
+                                  T_NOTPLACED)) {
+       make_swamp(x, y, hmap(x, y), 25);
+      } else { 
+        /* If rand_map_pos_temperature returns FALSE we may as well stop
+         * looking for swamp. */
+       plains_to_be_placed += swamps_to_be_placed; /* reactivate plains */
+       swamps_to_be_placed = 0;
+      }
+    }
+
+    if(deserts_to_be_placed > 0) {
+      /* Choose a random coordinate between TROPICAL_LEVEL and WET_LEVEL;
+        make_desert will expand them). */
+      if (rand_map_pos_temperature(&x, &y,
+                                  TROPICAL_LEVEL, WET_LEVEL,
+                                  T_NOTPLACED)){
+         make_desert(x, y, hmap(x, y), 40, map_temperature(x, y));
+      } else {
+       /* If rand_map_pos_temperature returns FALSE we may as well stop
+        * looking for dessert. (convert to plains) */
+       plains_to_be_placed += deserts_to_be_placed;
+       deserts_to_be_placed = 0;
+      }
+    }
+
+    /* Make the grass */
+    if(grass_to_be_placed > 0) {
+      if (rand_map_pos_temperature(&x, &y,
+                                  COLD_LEVEL, MAX_TEMP,
+                                  T_NOTPLACED)){
+       map_set_terrain(x, y, T_GRASSLAND);
+       grass_to_be_placed--;
+      } else {
+         plains_to_be_placed += grass_to_be_placed;
+         grass_to_be_placed = 0;
+      }
+    }
+
+    /* there is very important: this place all terrains when there
+       is not posibe for other types kip the 0, MAX_TEMP range. */
+    /* make the plains and tundras */
+    if(plains_to_be_placed > 0) {
+      if (rand_map_pos_temperature(&x, &y,
+                                  0, MAX_TEMP,
+                                  T_NOTPLACED)){
+       make_plain(x,y);
+      } else {
+       /* If rand_map_pos_temperature returns FALSE we may as well stop
+        * looking for plains. */
+       plains_to_be_placed = 0;
+      }
+    }
+
+  } while (forests_to_be_placed > 0 || deserts_to_be_placed > 0 
+          || grass_to_be_placed > 0 || plains_to_be_placed > 0 
+          || swamps_to_be_placed > 0 );
+
+  /* final test */
+  whole_map_iterate(x, y) {
+    assert(!not_placed(x,y));
+  } whole_map_iterate_end;
 }
 
 /*********************************************************************
@@ -814,7 +932,7 @@
     if (adjacent_river_tiles4(x, y) != 0
        || adjacent_ocean_tiles4(x, y) != 0
         || (map_get_terrain(x, y) == T_ARCTIC 
-           && map_temperature(x, y) < 8 * MAX_TEMP / 100)) { 
+           && map_temperature(x, y) < 0.8 * COLD_LEVEL)) { 
 
       freelog(LOG_DEBUG,
              "The river ended at (%d, %d).\n", x, y);
@@ -1027,56 +1145,6 @@
   river_map = NULL;
 }
 
-/**************************************************************************
-  make_plains converts 50% of the remaining grassland to plains, this should
-  maybe be lowered to 30% or done in batches, like the swamps?
-**************************************************************************/
-static void make_plains(void)
-{
-  whole_map_iterate(x, y) {
-    if (map_get_terrain(x, y) == T_GRASSLAND && myrand(100) > 50)
-      map_set_terrain(x, y, T_PLAINS);
-  } whole_map_iterate_end;
-}
-/****************************************************************************
-  Return TRUE if the terrain at the given map position is "clean".  This
-  means that all the terrain for 2 squares around it is either grassland or
-  plains.
-****************************************************************************/
-static bool terrain_is_clean(int map_x, int map_y)
-{
-  square_iterate(map_x, map_y, 2, x1, y1) {
-    if (map_get_terrain(x1, y1) != T_GRASSLAND
-       && map_get_terrain(x1, y1) != T_PLAINS) {
-      return FALSE;
-    }
-  } square_iterate_end;
-
-  return TRUE;
-}
-
-/**************************************************************************
-  we don't want huge areas of grass/plains, 
- so we put in a hill here and there, where it gets too 'clean' 
-**************************************************************************/
-static void make_fair(void)
-{
-  whole_map_iterate(map_x, map_y) {
-    if (terrain_is_clean(map_x, map_y)) {
-      if (!map_has_special(map_x, map_y, S_RIVER)) {
-       map_set_terrain(map_x, map_y, T_HILLS);
-      }
-      cardinal_adjc_iterate(map_x, map_y, x1, y1) {
-       if (myrand(100) > 66
-           && !is_ocean(map_get_terrain(x1, y1))
-           && !map_has_special(x1, y1, S_RIVER)) {
-         map_set_terrain(x1, y1, T_HILLS);
-       }
-      } cardinal_adjc_iterate_end;
-    }
-  } whole_map_iterate_end;
-}
-
 /****************************************************************************
   Lower the land near the polar region to avoid too much land there.
 
@@ -1117,6 +1185,21 @@
     }
   } whole_map_iterate_end;
 }
+/**************************************************************************
+ if there are room the isle is grownd by one else isle is deleted
+**************************************************************************/
+static void grown_tiny_isle(int x,int y, int nr) {
+  adjc_iterate(x, y, x1, y1) {
+    if(count_ocean_near_tile(x1,y1) == 7) {
+      map_set_terrain(x1, y1, T_NOTPLACED);
+      map_set_continent(x1, y1, nr);
+      MASS_SIZE(nr)++;
+      return;
+    }
+  } adjc_iterate_end;
+  map_set_terrain(x, y, T_OCEAN);
+  return;
+}
 
 /**************************************************************************
   make land simply does it all based on a generated heightmap
@@ -1142,27 +1225,36 @@
       if (hmap(x, y) < tres)
        map_set_terrain(x, y, T_OCEAN);
       else {
-       map_set_terrain(x, y, T_GRASSLAND);
+       map_set_terrain(x, y, T_NOTPLACED);
        count++;
       }
     } whole_map_iterate_end;
+
+    seaval = tres;
     if (count>total)
       tres*=11;
     else
       tres*=9;
     tres/=10;
   } while (abs(total-count)> maxval/40);
-
   renormalize_hmap_poles();
   make_polar_land(); /* make extra land at poles*/
-  make_mountains(maxval*8/10);
-  make_arctic();
-  make_tundra();
-  make_forests();
-  make_swamps();
-  make_deserts();
-  make_plains();
-  make_fair();
+  assign_continent_numbers(); /* count sizes */
+  whole_map_iterate(x, y) {
+      int nr = map_get_continent(x,y);
+      /* avoid too small oceans */
+      if (is_ocean(map_get_terrain(x, y)) && MASS_SIZE(nr) < 8) {
+       map_set_terrain(x, y, T_NOTPLACED);  
+      } 
+      /* avoid tiny isles */
+      else if (!is_ocean(map_get_terrain(x, y)) && MASS_SIZE(nr) == 1) {
+       grown_tiny_isle(x, y, nr);
+      }
+  } whole_map_iterate_end;
+
+  make_relief(); /* base relief on map */
+  make_arctic(); 
+  make_terrains();/* place forest/dessert/swamp/grass/tundra and plains */
   make_rivers();
 }
 
@@ -1202,63 +1294,6 @@
   } whole_map_iterate_end;
 }
 
-/**************************************************************************
-  Number this tile and recursive adjacent tiles with specified
-  continent number, by flood-fill algorithm.
-  is_land tells us whether we are assigning continent numbers or ocean 
-  numbers.
-**************************************************************************/
-static void assign_continent_flood(int x, int y, bool is_land, int nr)
-{
-  if (map_get_continent(x, y) != 0) {
-    return;
-  }
-
-  if ((is_land && is_ocean(map_get_terrain(x, y)))
-      || (!is_land && !is_ocean(map_get_terrain(x, y)))) {
-    return;
-  }
-
-  map_set_continent(x, y, nr);
-
-  adjc_iterate(x, y, x1, y1) {
-    assign_continent_flood(x1, y1, is_land, nr);
-  } adjc_iterate_end;
-}
-
-/**************************************************************************
-  Assign continent and ocean numbers to all tiles, set map.num_continents 
-  and map.num_oceans.
-  Continents have numbers 1 to map.num_continents _inclusive_.
-  Oceans have (negative) numbers -1 to -map.num_oceans _inclusive_.
-**************************************************************************/
-void assign_continent_numbers(void)
-{
-  /* Initialize */
-  map.num_continents = 0;
-  map.num_oceans = 0;
-  whole_map_iterate(x, y) {
-    map_set_continent(x, y, 0);
-  } whole_map_iterate_end;
-
-  /* Assign new numbers */
-  whole_map_iterate(x, y) {
-    if (map_get_continent(x, y) != 0) {
-      /* Already assigned */
-      continue;
-    }
-    if (!is_ocean(map_get_terrain(x, y))) {
-      map.num_continents++;
-      assign_continent_flood(x, y, TRUE, map.num_continents);
-    } else {
-      map.num_oceans++;
-      assign_continent_flood(x, y, FALSE, -map.num_oceans);
-    }      
-  } whole_map_iterate_end;
-
-  freelog(LOG_VERBOSE, "Map has %d continents and %d oceans", 
-         map.num_continents, map.num_oceans);
-}
 
 /****************************************************************************
   Return an approximation of the goodness of a tile to a civilization.
@@ -1672,9 +1707,9 @@
 static void adjust_terrain_param(void)
 {
   int total;
-  int polar = 5; /* FIXME: convert to a server option */
+  int polar = ICE_BASE_LEVEL * 100 / MAX_TEMP;
 
-  total = map.mountains + map.deserts + map.forestsize + map.swampsize 
+  total = map.mountains + map.deserts + map.forestsize + map.swampsize
     + map.grasssize;
 
   if (total != 100 - polar) {
@@ -2361,6 +2396,17 @@
 #define DMSIS 10
 
 /**************************************************************************
+  make_plains converts 50% of the remaining grassland to plains, this should
+  maybe be lowered to 30% or done in batches, like the swamps?
+**************************************************************************/
+static void make_plains(void)
+{
+  whole_map_iterate(x, y) {
+    if (map_get_terrain(x, y) == T_GRASSLAND && myrand(100) > 50)
+      map_set_terrain(x, y, T_PLAINS);
+  } whole_map_iterate_end;
+}
+/**************************************************************************
   island base map generators
 **************************************************************************/
 static void mapgenerator2(void)
diff -ruN -Xfreeciv/diff_ignore freeciv/server/mapgen.h freeciv_/server/mapgen.h
--- freeciv/server/mapgen.h     2004-08-13 21:08:52.000000000 +0200
+++ freeciv_/server/mapgen.h    2004-08-15 08:18:59.977678296 +0200
@@ -13,7 +13,6 @@
 #ifndef FC__MAPGEN_H
 #define FC__MAPGEN_H
 
-void assign_continent_numbers(void);
 void map_fractal_generate(void);
 void create_start_positions(void);
 
diff -ruN -Xfreeciv/diff_ignore freeciv/server/maphand.c 
freeciv_/server/maphand.c
--- freeciv/server/maphand.c    2004-08-13 21:08:52.000000000 +0200
+++ freeciv_/server/maphand.c   2004-08-15 09:25:06.467680160 +0200
@@ -32,7 +32,6 @@
 #include "citytools.h"
 #include "cityturn.h"
 #include "gamelog.h"
-#include "mapgen.h"            /* assign_continent_numbers */
 #include "plrhand.h"           /* notify_player */
 #include "sernet.h"
 #include "srv_main.h"
@@ -41,6 +40,74 @@
 
 #include "maphand.h"
 
+
+int mass_size[2 * MAP_NCONT];
+/**************************************************************************
+  Number this tile and recursive adjacent tiles with specified
+  continent number, by flood-fill algorithm.
+  is_land tells us whether we are assigning continent numbers or ocean 
+  numbers.
+**************************************************************************/
+static void assign_continent_flood(int x, int y, bool is_land, int nr)
+{
+  if (map_get_continent(x, y) != 0) {
+    return;
+  }
+
+  if (!XOR(is_land , is_ocean(map_get_terrain(x, y)))) {
+    return;
+  }
+
+  map_set_continent(x, y, nr);
+  MASS_SIZE(nr)++;
+
+  adjc_iterate(x, y, x1, y1) {
+    assign_continent_flood(x1, y1, is_land, nr);
+  } adjc_iterate_end;
+}
+
+/**************************************************************************
+  Assign continent and ocean numbers to all tiles, set map.num_continents 
+  and map.num_oceans.
+  Continents have numbers 1 to map.num_continents _inclusive_.
+  Oceans have (negative) numbers -1 to -map.num_oceans _inclusive_.
+**************************************************************************/
+void assign_continent_numbers(void)
+{
+  int i;
+
+  /* Initialize */
+  for(i = 0; i < 2 * MAP_NCONT; i++) {
+    MASS_SIZE(i) = 0;
+  }
+  map.num_continents = 0;
+  map.num_oceans = 0;
+    
+  whole_map_iterate(x, y) {
+    map_set_continent(x, y, 0);
+  } whole_map_iterate_end;
+
+  /* Assign new numbers */
+  whole_map_iterate(x, y) {
+    if (map_get_continent(x, y) != 0) {
+      /* Already assigned */
+      continue;
+    }
+    if (!is_ocean(map_get_terrain(x, y))) {
+      map.num_continents++;
+      assert ( map.num_continents < MAP_NCONT);
+      assign_continent_flood(x, y, TRUE, map.num_continents);
+    } else {
+      map.num_oceans++;
+      assert ( map.num_oceans < MAP_NCONT);
+      assign_continent_flood(x, y, FALSE, -map.num_oceans);
+    }      
+  } whole_map_iterate_end;
+
+  freelog(LOG_VERBOSE, "Map has %d continents and %d oceans", 
+         map.num_continents, map.num_oceans);
+}
+
 static void player_tile_init(int x, int y, struct player *pplayer);
 static void give_tile_info_from_player_to_player(struct player *pfrom,
                                                 struct player *pdest,
diff -ruN -Xfreeciv/diff_ignore freeciv/server/maphand.h 
freeciv_/server/maphand.h
--- freeciv/server/maphand.h    2004-08-13 21:08:52.000000000 +0200
+++ freeciv_/server/maphand.h   2004-08-15 10:21:29.184429048 +0200
@@ -49,6 +49,15 @@
   short last_updated;
 };
 
+/* this is used for generator 2-4 and in assign_continent number */
+#define MAP_NCONT 300
+
+/* signus safe way for nr continent <0 or >0 */
+extern int mass_size[2 * MAP_NCONT];
+#define MASS_SIZE(nr) (mass_size[FC_WRAP((nr), 2 * MAP_NCONT)]) 
+void assign_continent_numbers(void);
+
+
 void global_warming(int effect);
 void nuclear_winter(int effect);
 void give_map_from_player_to_player(struct player *pfrom, struct player 
*pdest);
diff -ruN -Xfreeciv/diff_ignore freeciv/server/stdinhand.c 
freeciv_/server/stdinhand.c
--- freeciv/server/stdinhand.c  2004-08-13 21:08:52.000000000 +0200
+++ freeciv_/server/stdinhand.c 2004-08-15 08:37:17.122886872 +0200
@@ -369,7 +369,7 @@
 
   GEN_INT("grass", map.grasssize,
          SSET_MAP_GEN, SSET_ECOLOGY, SSET_SITUATIONAL, SSET_TO_CLIENT,
-         N_("Amount of grass squares"), "", NULL,
+         N_("Amount of grass and plains squares"), "", NULL,
          MAP_MIN_GRASS, MAP_MAX_GRASS, MAP_DEFAULT_GRASS)
 
   GEN_INT("forests", map.forestsize,
diff -ruN -Xfreeciv/diff_ignore freeciv/utility/shared.h 
freeciv_/utility/shared.h
--- freeciv/utility/shared.h    2004-08-13 21:08:53.000000000 +0200
+++ freeciv_/utility/shared.h   2004-08-15 08:00:17.424332344 +0200
@@ -101,8 +101,8 @@
      ? ((value) % (range) != 0 ? (value) % (range) + (range) : 0)           \
      : ((value) >= (range) ? (value) % (range) : (value)))
 
-#define BOOL_VAL(x) ((x)!=0)
-
+#define BOOL_VAL(x) ((x) != 0)
+#define XOR(p,q)   (!(p) != !(q))
 /*
  * DIVIDE() divides and rounds down, rather than just divides and
  * rounds toward 0.  It is assumed that the divisor is positive.